Integrated engine dilution control
AssigneeGeneral Motors Corporation
InventorsRonald Jay Pierik, Daniel Francis Kabasin
Life of this patent
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Abstract
Integrated dilution control for diluting internal combustion engine intake air through control of relative timing between engine cylinder intake and exhaust valve events integrated with control of recirculation of engine exhaust gas through an external exhaust gas conduit with periodic recalibration of modeled relationships between dilution control parameters to correct for effects of dilution control system aging. Internal dilution provided through control of relative valve timing further may be maximized and external dilution provided through the external conduit minimized.
Claims11
An integrated dilution control method for controlling dilution of intake air passing through an intake manifold of an internal combustion engine having variable valve timing control means for controlling internal dilution by controlling the relative timing of engine cylinder intake and exhaust valve events and having exhaust gas recirculation (EGR) control means for controlling external dilution by controlling recirculation of engine cylinder exhaust gasses through an EGR conduit, the method comprising the steps of:
- storing a calibrated model of a relationship between predetermined dilution control parameters;
- sensing presence of a predetermined operating condition when dilution of the intake air is required;
- controlling dilution when the predetermined operating condition is present, by:
- (a) generating a desired dilution value;
- (b) calculating a desired intake manifold air pressure as a predetermined function of the desired dilution value;
- (c) generating a valve timing command as a function of the desired intake manifold air pressure as the valve timing command providing internal dilution sufficient to drive intake manifold air pressure toward the desired intake manifold air pressure;
- and
- (d) controlling internal dilution by controlling relative timing of engine cylinder intake and exhaust valve events in accord with the valve timing command.
An integrated dilution control method for controlling a degree of dilution of intake air ingested by an internal combustion engine having variable valve timing control means for controlling the relative timing of engine cylinder intake and exhaust valve events, and having an exhaust gas conduit through which combustion products are exhausted from engine cylinders, with an exhaust gas recirculation (EGR) conduit opening, on a first conduit end, into the exhaust gas conduit and opening, on a second end, into an engine intake manifold, the EGR conduit having an EGR valve therein responsive to an EGR command to vary a degree of opening of the EGR valve, the method comprising the steps of:
- storing a predetermined model describing correspondence between predetermined dilution control parameters;
- determining presence of an engine operating condition under which dilution control is desired;
- integrating internal and external dilution control when the engine operating condition is determined to be present, by (a) referencing a desired dilution factor, (b) calculating a valve timing control command as a predetermined function of the desired dilution factor, (c) calculating an EGR control command as a predetermined function of the desired dilution factor, (d) controlling valve timing in accord with the valve timing control command and controlling the degree of opening of the EGR valve in accord with the EGR control command;
- and
- adjusting the stored model when the engine operating condition is not determined to be present, by (a) determining current values of the dilution control parameters, (b) determining a correspondence between the current values, and (c) varying the stored model so that it further describes the correspondence between the current values of the dilution control parameters.
Dependencies are inferred from the claim text.